Return-Path: Received: from mail-oi0-f43.google.com ([209.85.218.43]:36246 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824AbbJGXRm (ORCPT ); Wed, 7 Oct 2015 19:17:42 -0400 Received: by oibi136 with SMTP id i136so18080776oib.3 for ; Wed, 07 Oct 2015 16:17:41 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20151007200831.GB27924@fieldses.org> References: <1444240482-11287-1-git-send-email-trond.myklebust@primarydata.com> <20151007200831.GB27924@fieldses.org> Date: Wed, 7 Oct 2015 19:17:41 -0400 Message-ID: Subject: Re: [PATCH] SUNRPC: Use MSG_SENDPAGE_NOTLAST when calling sendpage() From: Trond Myklebust To: Bruce Fields Cc: Linux NFS Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Oct 7, 2015 at 4:08 PM, Bruce Fields wrote: > On Wed, Oct 07, 2015 at 01:54:42PM -0400, Trond Myklebust wrote: >> If we're sending more pages via kernel_sendpage(), then set >> MSG_SENDPAGE_NOTLAST. > > Given that we've survived without this a while, I assume this is a hint > that may provide better performance in some cases (have you seen that?) > and that it doesn't have to be 100% correct? See the original motivation in: commit 2f5338442425 ("tcp: allow splice() to build full TSO packets") and the later bugfix (which actually introduces MSG_SENDPAGE_NOTLAST): commit 35f9c09fe9c7 ("tcp: tcp_sendpages() should call tcp_push() once") > In which case, looks fine, will queue up for 4.4.... Sure. It's a minor performance enhancement, so there is no immediate rush.